Among wireless tags, there is a wireless tag known in the art that may be attached to radio-wave reflecting materials such as metallic surfaces or radio-wave absorbing materials such as liquid-containing materials. Japanese Laid-Open Patent Application No. 2008-117276, for example, discloses a non-contact type data transmission/reception object as an example of such a wireless tag that may be attached to the radio-wave reflecting or absorbing materials. Such a non-contact type data transmission/reception object includes a substrate, an adhesive layer formed at both ends in a longitudinal direction of one surface of the substrate, and an inlet including an IC chip and an antenna pattern that is provided via the adhesive layer. In the non-contact type data transmission/reception object, parts of the inlet where the antenna pattern is provided are folded in layers, and a part of the inlet where the IC tag and the antenna pattern are provided is arranged at a position having a predetermined distance from the substrate. Japanese Laid-Open Patent Application No. 2009-231870 discloses a technology on the wireless tag that may be attached to an object regardless of its material. In this technology, a half-loop antenna is attached to a spacer made of dielectric.
The wireless tag (i.e., the non-contact type data transmission/reception object) disclosed in Japanese Laid-Open Patent Application No. 2008-117276 includes a three-dimensional antenna structure that is formed by folding parts of the inlet provided with the antenna pattern in layers. However, since the antenna pattern is not provided beneath the IC chip, image current may not be excited. As a result, the current may not be amplified.
Meanwhile, in the configuration of the wireless tag disclosed in Japanese Laid-Open Patent Application No. 2009-231870, the dielectric spacer is additionally provided. Further, the manufacturing process of this wireless tag may be complicated; for example, the wireless tag may be manufactured by providing a hole in the dielectric spacer, embedding the IC chip in the hole, fixing the antenna pattern on the spacer, and covering the entire tag with a molded material. As a result, the manufacturing cost may be increased.